has anyone used one of these? I can't use it in a chair but if I lay on my stomkach and put it on my back it doesn't seem too bad bbut I don't want to hurt myslef. sorry today is a bad day for trypiing.

Yes, I have one of these, I think it works pretty good....I know they say to NOT lay on it, but I sometimes do for a short time. Works GREAT on the shoulder blades I'm not a doctor, but I don't think it can hurt anything. You need to do whatever helps to ease the pain, right?